Digital Food Dispenser - Mouse

Technical Manual

Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com), Millisecond

Created: January 07, 2015

Last Modified: January 21, 2025 by K. Borchert (katjab@millisecond.com), Millisecond

Script Copyright © Millisecond Software, LLC

Background

This script implements a Digital Food Dispenser similar to the one described in:

Van Koningsbruggen, G.M., Veling, H., Stroebe, W. & Aarts, H. (2014). Comparing two psychological interventions in reducing impulsive processes of eating behaviour: Effects on self-selected portion size. British Journal of Health Psychology, 19, 767–782.

Duration

2 minutes

Description

Participants view a food dispenser. By pressing the Mouse button down they "open" the Food Dispenser. By lifting the Mouse button they "close" the Food Dispenser and end the session.

Procedure

• 2 trials: 1 food dispenser with cherries and 1 food dispenser with bananas; order is randomly determined
• Mouse down: the dispenser "opens": fruit pieces "fall out" and a gray cover starts to cover the food dispenser
to simulate that it empties out
• Mouse up: the dispenser "closes" -> trial comes to an end
• every 100ms (default) of pressing the Mouse earns the participant 1 point => max. 500 points can be earned (then the dispenser is empty)

Stimuli

provided by Millisecond

Instructions

provided by Millisecond; edit under section Editable Instructions

Summary Data

File Name: digitalfooddispensermi_summary*.iqdat

Data Fields

NameDescription
inquisit.version Inquisit version number
computer.platform Device platform: win | mac |ios | android
startDate Date the session was run
startTime Time the session was run
subjectId Participant ID
groupId Group number
sessionId Session number
elapsedTime Session duration in ms
completed 0 = Test was not completed
1 = Test was completed
maxPoints The maximum number of points that can be gained for one food dispenser (default: 500)
meanResponseDuration Mean response duration in ms (how long Spacebar was pressed on average) across dispensers
meanPoints Mean points gained across dispensers (Max: 500)

Raw Data

File Name: digitalfooddispensermi_raw*.iqdat

Data Fields

NameDescription
build Inquisit version number
computer.platform Device platform: win | mac |ios | android
date Date the session was run
time Time the session was run
subject Participant ID
group Group number
session Session number
blockCode Name of the current block
blockNum Number of the current block
trialCode Name of the current trial
trialNum Number of the current trial
dispenser 1 = cherries
2 = bananas
stimulusItem The presented stimuli in order of trial presentation
response The participant's response
correct The correctness of the response (1 = correct; 0 = incorrect)
latency The response latency (in ms)
currentResponseDuration The amount of time the Spacebar was pressed (in ms) for the current food dispenser
currentPoints Stores the points of the current food dispenser session (resets for each food dispenser)
totalPoints Stores the points earned across food dispensers

Parameters

The procedure can be adjusted by setting the following parameters.

NameDescriptionDefault
increaseInterval Another point is added for every 100ms (default; should not be set lower than vertical refreshrate of monitor which is ~17ms for a 60Hz monitor)
that the Mouse is NOT pressed
maxPoints The maximum number of points that can be gained
the product of increaseinterval and maxpoints controls how long it takes to 'drain' the dispenser completely
500
finalCoverHeight The height of the final gray cover ( should only be messed with if different pictures are used)